Delay/chorus with octave up/down effects - better? worth it?

[Mark Hammer]

Sitting in the car today, waiting for my wife to come out of the store, I was listening to Led Zep's "Since I've Been Lovin' You" on the radio, and thinking about octave-down and octave-up effects.  More specifically, I started thinking about what might make such things sound better with a little extra work (in contrast to the approach frequently sought out here, which is "What is the absolute simplest version I can build of each?").

What I started wondering about was whether there is anything aesthetically more pleasing or psychoacoustically important about separating the octave signal in time from the real-time signal.  In other words, imagine that a pedal can be coaxed into producing either one octave up or one octave down from the input signal (in mono or poly), and before the two added signal is mixed in with the original, it is delayed a bit, maybe even chorussed (i.e., delay time is modulated a bit).

1) Has anyone ever done an experiment like this and what did you think of it?  If so, were there parameters that you could suggest need to be observed.

2) If no one has ever done anything like that, what is your best guess of how it MIGHT sound?

Again, note that what I am suggesting is essentially a pedal that attempts to make the added tone sound a little more like a separate instrument source than merely an octave pedal with a chorus after it.

My own hunch is that it might be of more use for an octave up than for an octave down.  I say this largely because the very act of frequency division produces a slight time lag itself.  As a result, octave-down tends to sound a little more like two instruments than octave up does.

[Fp-www.Tonepad.com]

I have done this:

Split the signal, one path goes clean to the mixer. The other one gets a delay first and then a pitch shift. This would be like your basic harmonizer, if you will.

Processing delayed signal independently and then mixing it with dry signal does make some nice effects.

... I don't know if this is actually related to what you were talking about.

[StephenGiles]

Sitting in the car today, waiting for my wife to come out of the store,

I'm not sure Anne would approve of that Mark, she would say that it should be the other way round!

More specifically, I started thinking about what might make such things sound better with a little extra work (in contrast to the approach frequently sought out here, which is "What is the absolute simplest version I can build of each?").

Thankyou - my sentiments entirely! This echoes my thoughts on many of the Penfold projects in old editions of PE. The octave up question - well, it's there in the EH guitar synthesiser, because one VCO is always one octave above the input frequency and I remember putting the output of this through an Electric Mistress and mixing the result with untreated guitar and octave down from a Microsynth. The result - a massive sound. Sadly, my Guitar synth board no longer works!
Stephen

[R.G.]

Hmmm...

You might try doing a pair of Dome filters, too.

Two all pass networks, with a constant 90degree phase difference between them across a wide band. They're used in I/Q modulators. But they would help destroy the phase coherence of signal/octave that makes an octave up/down sound like an effect, not another instrument.

[puretube]

slow phasing one of the signals (wet only), will do nicely... (IMHO).

[Connoisseur of Distortion]

my experience (from a related, albeit different test) would suggest a "feedbacky" kind of sound for the chorus.

test mentioned was about an hour of messing around with a pair of whammy pedals. at one point we detuned (chorus-like) after feeding it through an octaver. the dry signal was normal, but in the background you could hear what sounded like an overtone singing (in a thick, warbly voice) along. we tried shifting using a delay at some point, but we couldn't really find a good use for the sound

mind you, this isn't an effect loop inside the pitch shifter (which is the point of this convo, i think) but that's my experience on a similar topic. try it out and inform us!

and that comment about simple builds hit a little too close to home  :lol:

[dave h.]

this might be considered the same topic:

we have the technology for pedal tuners, right? signal in, estimated note shows up on little screen, LED shows up saying how sharp/flat. (boss tu-2)

this means that you can program a list of "note" frequencies (a=440, etc.) and the pedal can

A) identify the input signal's frequency
B) compare it to the list of in-tune notes
C) tell you what the note youre aiming for is

i think ring modulators use this kind of logic without recognizing the input, but still adding and subtracting the "carrier" frequency from the input frequency.

maybe this is the idea behind most pitch shifters. or maybe MIDI synthesizing (no idea how that works). but couldnt you use this tuner circuit to send a signal to another electronic instrument?

for example, the pedal sends a second output to a keyboard, or other midi device or something, which then actually mixes a second "instrument" with the input?

if we have whammies we could use that same circuit to make that instrument play any harmony with the original signal.

then use a delay circuit to delay the midi output a tiny bit.

right? same idea?